Apparatus for cracking hydrocarbon oils



Dec. 8, 1931. D. A. DEAN 1,835,383

I APPARATUS FOR CRACKING HYDROCARBON OILS Filed Sept. 20, 1927 2 Sheets-Sheet 1 [maid-WV:

Dec. s; 1931. A DEAN 1,835,383

APPARATUS FOR CRACKING HYDROCARBON OILS Fil Sept. 20. 1927 2 Sheets-Sheet 2 Patented Dec. 8, 1931 PATENT OFFICE DANIEL A. DEAN, OF ENIID, OKLAHOMA APPARATUS FOR CRACKING HYDROCARIBON OILS Application filed September 20, 1927. Serial No. 220,657.

This invention'relates to improvements in process and apparatus for cracking hydrocarbon oils and distilling crude petroleum and the like. g I

The objects of the invention are, first, to lessen the danger due to carbon deposits on the hot surfaces of the heating vessels and thereby increase the length of'time thatthe apparatus may be operated with safety;

second, to provide a novel and eflicient means for heating the reflux oil during its passage from the reflux tower or dephlegmator to the vaporizing retort; third, to provide a means for removing a largepart of the carbon carried by the'refluxed oil during'the passage of such oil from the dephlegmator to the retort; fourth, to provide a' means for trapping and removingthe carbon carried by the refluxed oil and thrown down by the reaction caused by vheat after the oil enters the retort and thereby prevent such carbon from reaching and being deposited upon the heated surface or fire sheet of the retort; and, fifth, to provide a heating furnace with means whereby a portion of the hot burned gases being discharged therefrom may be mixed with fresh air and heated and returned to the combustion chamber for supporting combustion and obtaining high heat efliciencies and for the prevention of ()Xldfl'.

tion.

The invention consists in the novel construction, combination and arrangement and process hereinafter described and particularly claimed.

In the accompanying drawings, illustrating the invention,

Figure 1 is a longitudinal, vertical section through an oil cracking apparatus showing one form of embodiment of my invention.

Figure 2 is a transverse sectionthereof, on-

line 2-2 of Fig. 1.

Referring to the drawings, 3 designates a horizontally extending retort in which the oil to be cracked or processed is heated and vaporized. Y

The retort 3 is supported by the walls of afurnace 4 and the bottom portion of the retort constitutes the major portion of the top wall of the combustion chamber 5 of the furnace. The combustion chamber extends horizontally beneath the retort from its inlet portion 6 at its forward end which receives the fuel and air for supporting combustion to a down draft passage 7 which forms the outlet portion of the chamber. The lower end of the down draft passage 7 1s in communication with the bottom of a stack 8 through which the products of combustion from the furnace are discharged.

The inlet portion 6 of the combustion chamber 5 is in the form of a fire box havmga suitable grate therein for the receptlon of solid, liquid or'gaseous fuel. In the drawings I have shown a burner 9 which may be of any approved type for the introguction of liquid or gaseous fuel to the fire Oppositely disposed ducts or passages 10' and 11 are provided on the forward and rearward sides of the lower portion of the down draft passage 7, and these boxes are connected by a series of tubes 12 which extend through the passage 7 in spaced relation to-each other and to the parallel walls of the passage. The forward box 10 is connected to the inlet portion 6 of the furnace below the grate therein by a horizontally extending flue 13.

Located between the stack 8 and the furnace 4 is a fan or blower 14 which may be of any approved type. The discharge passage of the fan 14 is connected to the duct or box 11 and the inlet passage of the fan is connected to a pipe 15 which leads to and com-- municates with the lower portion of the stack 8. The pipe 15 is provided with an upwardly extending branch pipe 16 which is open at its upper end for admitting fresh air to the pipe 15 and fan 14. The quantity. of fresh air which the fan 14 is permitted to draw into the pipes 16 and 15 is controlled by an adjustable gate or damper 17 and the quantity of burnt gases which the fan 14 is permitted to draw into the pipe 15 from the stack 8 is controlled by an adjustable gate or damper 18. The fan 14 is operable to draw the combined fresh air and spent gases into the pipes 15 and 16 and to blow them through the box 11, the bank of tubes 12, the box 10 and the flue 13 into the inlet portion or fire box 3 of the furnace. This combined fresh air and spent gases together with the fuel introduced by the burner 9 support combustion within the chamber 5 for heating the retort 3; and the fresh air and spent gases are heated as they pass through the tubes 12 by the fire and hot burnt gases passing through the lower portion of the down draft passage 7 and around the tubes. By adjusting the gates or dampers 17 and 18 the relative proportions of fresh air and spent gases blown into the combustion chamber may be nicely regulated for high heat efficiencies and the elimination of oxidation. I have found that very good results are obtained by adjusting the gates so that the fan 14 will draw about ten per cent. of spent gases from the stack 8 and the balance or ninety per cent. of fresh air through the branch pipe 16.

Leading from the top of the retort 3 is an upwardly extending pipe 19 the upper end of which communicates with the lower portion of a reflux tower or dephlegmator 20 which may be of any approved form. The vapors are conducted from the retort 3 to the reflux tower 20 through the pipe 19, and the reflux oil passes from the tower 20 through a pipe 21 the upper end of which is connected to the bottom of the tower and the lower end of which is connected to a drum or header 22 which forms the inlet to a series of tubes 23' which extend transversely through the down draft assage 7 of the combustion chamber of the urnace above the tubes 12. The tubes 23 are arranged in horizontal banks in superposed spaced relation and they extend through and are supported by the side walls of the furnace. The outwardly extending ends of the tubes 23 are connected by headers 24, as shown in Fig. 2, in a manner to form a continuous, upwardly directed passage from the inlet header 22 to the discharge or outlet ends of the uppermost bank of tubes 23 which discharge into a drum 25. This drum 25 is supported by a suitable frame structure 26 arranged at one side of the furnace as clearly shown in the drawings.

Leading from the top of the drum 25 is a pipe 27 which extends into the retort 3 and is provided on its inner end with upwardly and downwardly discharging branches 28 and 29, respectively, These branches 28 and 29 discharge into a receiving compartment 30 formed within the rearward end portion of the retort 3 by an inclined bottom wall 31 spaced above the bottom of the retort and having a vertically extending free end 32 forming an overflow portion emptying into the main interior of the retort exteriorly of the compartment 30 for purposes presently appearing. The, pipe 21, header 22, tubes 23, headers 24, drum 25 and pipe 27 form the passage for the reflux oil "which flows from the bottom of the reflux tower 20 to the compartment 30 within the retort 3.

The cross sectional area of the drum 25 is much greater than that of the bank of tubes 23 discharging into the same, and than that of the pipe 2. leading from the drum, so that the velocity of the refluxed oil, as it passes through the drum 25, is decreased to such an extent that a large percentage of the carbon in suspension therein will settle out and be collected within the drum.

As the reflux oil passes upwardly through the tubes 23 it is heated,countcr current, to the temperature of the body of oil within the retort 3, by the hot and burning gases pass ing through the down draft passage 7 of the combustion chamber of the furnace and around the tubes 23; and, after the oil passes into the retort 3, it is further heated and vaporized and again passed through the vapor line 19 and the cycle repeated.

The receiving compartment 30 forms a quiet zone within the retort for the reception of the refluxed oil which is discharged through the downwardly directed branch pipe 29 while such of the oil that is revaporized in passing through the tubes 23 is discharged through the upwardly directed branch pipe 28 into the vapor space above the oil within the retort. This method of introducing the reflux oil to the retort prevents any disturbance in the quiet zone by the belching of vapors and fixed gases under the surface of the. oil; The refluxed oil passes from the compartment 30 over the overflow portion 32 of the wall 31 into the main interiorv of the retort.

Theobject in creating the quiet zone within the compartment 30 with its bottom wall 31 spaced above the bottom of the retort is to prevent heavy'residuum and suspended carbon carried into the retort by the refluxed oil from being deposited upon the fire sheet of the retort 3 Where itwould cause bagging of the sheet or undue local heating of the retort.

Leading from the retort 3 are two pipes 33 and 34 provided with valves 35 and 36, respectively The pipe 34 has an intake end which is open near the bottom of the space for the main body of oil within the retort; and the pipe 33 has an intake end which is open near the bottom of the receiving compartment 30. Leading from the bottom of the velocity decreasing drum 25 is a pipe 37 provided with a valve 38. Thepipes 33, 34 and 37 are connected to and form branches of a common pipe 40 having an open end shown in cross section at the elbow joint connecting pipe 37 with the vertical portion of pipe 40. The contents of the main body of the retort may be drawn off through pipes 34 and 40. Through pipes 33, 37 and 40 the residue collected within the drum 25'and within the receiving compartment 30 of the retort 3 may be drawnoff by any suitable means. Leading from the header 22 is a valve controlled pipe 41 through which residue collected within the header may be drawn off.

Connected to the upper end of the reflux tower 20 and extending downwardly there-- from is a pipe 42 provided with a valve 43 and having its lower end connected to the lower portion of a suitable bubble tower 44. The lighter vapors entering the reflux tower 20 through the pipe 19 reach the top of the tow-er and are held at the pressure of the retort 3 and are released to a lower pressure within the bubble tower 44 by opening the valve 43. The hot vapors entering the bottom of the bubble tower 44 ascend therein and pass from the upper portion thereof through a pipe 45. The reflux dropping to the bottom of the bubble tower 44 may be drawn therefrom through a suitable valve controlled pipe 39 connected to the bottom of the tower.

The vapor pipe 45 extends downwardly from the upper portion of the bubble tower 44 and has its lower end connected to the upper end of the coil 46 of a water-cooled condenser 47 for the recovery of the fixed gases and the desired liquid. The lower end of the coil 46 is connected to a suitable separating drum 48 within which the permanent and fixed gases are separated from the cone densed vapors. Extending from the upper and lower portions of the drum 48 are valve controlled pipes 49 and 50 through which the gases and condensed vapors, respectively, may be drawn from the drum.

The oil to be treated is introduced to the system through a valve controlled supply pipe 51 which enters the reflux tower 20 and discharges into the upper portion thereof.

I claim as my invention:

1. An apparatus for distilling oil comprising a retort, a wall therein providinga receiving compartment having a bottom spaced above the bottom of the retort and having an overflow portion emptying into the main interior of the retort exteriorly of the receiving compartment, the vapor spaces of the retort and receiving compartment being in free communication with each other, a furnace beneath the retort, a reflux dephlegmator, a vapor pipe leading from the upper portion of the retort to the dephlegmator, a vapor pipe leading from the upper portion of the dephlegmator, a series of connected tubes extending through the combustion chamber of the furnace and having an inlet end and an outlet end and forming a continuous passage, means for conducting reflux oil from the dephlegmator to the inlet end of the series of tubes, pipe in communication with the outlet end of the series of tubes and having two discharging branches on its discharging end within the receiving compartment, one of said branches discharging upwardly and the other of said branches discharging downwardly.

2. An apparatus for distilling oil comprising a retort, a wall therein providing a receiving compartmenthaving a bottom spaced above the bottom of the retort and having an overflow portion emptyinginto the main interior of the retort exteriorly of the receiving compartment,the vapor spaces of the re tort and receiving compartment being in free communication with each other, a furnace beneath the retort, a reflux dephlegmator, a vapor pipe leading from the upper portion of the retort to the dephlegmator, a vapor pipe leading from the upper portion of the dephlegmator, a'series of connected tubes extending through the combustion chamber of the furnace and having an inlet end and an outlet end and forming a continuous passage, means for conducting reflux oil from the dephlegmator tothe inlet end of the series of tubes, a velocity decreasing, residue collecting drum communicating with the outlet end of the series of tubes, and a pipe leading from the drum and having two discharging branches on its discharging end within the receiving compartment, one of said branches discharging upwardly and the other of said branches discharging downwardly.

3. An apparatus for distilling oil comprising a retort, a wall therein providing a receiving compartment having a bottom spaced above the bottom of the retort and having an overflow portion emptying into the main interior of the retort exteriorly of the receiving compartment, a furnace beneath the retort, a reflux dephlegmator, a vapor pipe leading from the upper portion of the retort to the dephlegmator, a vapor pipe leading from the upper portion of the dephlegmator, a series of connected tubes extending through the combustion chamber of the furnace and having an inlet end and an outlet end and forming a continuous passage, means for conducting reflux oil from the dephlegmator to the inlet end of the series of tubes, means including a velocity decreasing, residue collecting drum exteriorly of the retort for conducting reflux oil from the outlet end of the series of tubes to the receiving compartment, and a residue pipe connected to the drum and having two valve controlled branches oneof which communicates with the lower portion of the receiving compartment and the other of which communicates with the lower portion of the retort.

4. The process of treating oil which comprises heating a body of oil in a retort to form vaporous fractions thereof, refluxing the vapors in contact with raw oil to be treated, passing the reflux oil through a heated coil, allowing solid material in the heated reflux oil to settle out, then passing the reflux oil to a zone within the retort but .separated'from the main body of oil being directly to the vapor space of the retort while liquid portions of the heated reflux oil simultaneously pass beneath the surface of the oil in said zone to unite with other liquid portions of the oil therein, whereby further quantities of solid material in the reflux oil are allowed to separate out in a substantially quiescent pool and then uniting the reflux oil with the main body of oil.

5. In a process of heating oil in a retort wherein vapors therefrom are refluxed with raw oil to form a reflux oil, which is then heated, the steps which include passing the heated reflux oil into a zone within the retort but separated from the main body of oil therein in such a manner that vaporized portions of the heated reflux oil pass directly to the vapor space of the retort while liquid portions of the heated reflux oil simultaneously pass beneath the surface of the oil in said zone to unite with other liquid portions of the oil therein, whereby any solid material in the reflux oil is allowed to separate out in a substantially quiescent pool, and then uniting r the reflux oil with the main body of oil in the retort.

In testimony whereof I affix my signature.

DANIEL A. DEAN. 

